Increasing carbon dioxide makes our food less nutritious

High levels of atmospheric carbon dioxide negatively impact key mineral nutrients in plants, reducing the nutrition derived from their consumption, a recent study reveals. journal article in the Trends in Plant Science Journal which summarizes the results of several studies. The study by French scientists explained that almost all C3 plants – which use the C3 pathway for photosynthesis where the first carbon compound has three carbon atoms – that are exposed to high levels of carbon dioxide show a reduction nutrients such as nitrogen, phosphorus and potassium. , iron, zinc, magnesium and sulfur.

Estimates reveal that compared to the pre-industrial era, atmospheric carbon dioxide levels are now 50 percent higher. In 2022, global average carbon dioxide levels reached 417.06 parts per million, leading to another record increase.

In May of this year, carbon dioxide levels measured by NOAA’s Global Monitoring Laboratory averaged 424.0 parts per million (ppm), an increase of 3.0 ppm from May 2022.

While being a vital resource for plants, carbon dioxide is also one of the main greenhouse gases. Considering that the majority of plants on the planet, including cereals like wheat, rice, barley and oats, use the C3 pathway, the review article sounded the alarm about the increasing levels of carbon dioxide which impacts not only the quantity of food produced, but also its quality.

Although this phenomenon was recorded around two decades ago, recent evidence has helped establish the extent of its impact, the review article states.

Cultures bear the brunt of human actions from above and below

Although the review article has resurfaced the debate on climate change and its impact on the nutritional value of crops, in the Indian context, the topic gains importance given the country’s difficulties in meeting food and nutritional needs. According to Global Hunger Index (GHI) 2022, India ranks 107th out of 121 countries and has a hunger problem described as serious. The GHI 2022 also said that India has the highest rate of child wasting (children too thin for their height) in the world. In 2022, a report published in BMJ Global Health highlighted that severe acute malnutrition had significantly decreased. increased in India over the last two decades.

In light of these results, the fact that crops are becoming inherently less nutritious is concerning, said Dr. Hemapriya Natesan, founder and CEO. My little Moppetan e-commerce platform for children’s food products.

Dr. Natesan explained that early food choices are key to establishing healthy eating habits in the future, and optimal nutrition at the right time makes all the difference. While this may seem like a well-established fact, as a mother and physician, Dr. Natesan has both seen the impacts of inadequate nutrition and faced challenges in providing optimal nutrition in a landscape where grain-rich in sugar are the norm.

When you add the influence of increasing carbon dioxide levels to the above scenario, it makes things more complicated.

While nutritional challenges are only part of the problem, high levels of carbon dioxide are also changing the balance of the soil, making it difficult to implement sustainable agricultural practices, explained G.RavikanthAssociate Professor at the Suri Sehgal Center for Biodiversity and Conservation, Ashoka Trust for Research in Ecology and the Environment (ATREE), Bangalore.

“When plants are exposed to more carbon dioxide, photosynthesis increases, leading to an increase in biomass. To meet the new demand, plants try to draw more nutrients from the soil. Additionally, carbon dioxide also affects soil microflora, thereby impacting soil decomposition rates and influencing nutrients available to plants,” he said. The vicious cycle makes it difficult to grow without adding external nutrients, he noted.

Much like India’s troubled nutritional landscape, the Global Soil Biodiversity Atlas released in 2016 found that Indian soil organisms are at high risk due to various threats such as pollution, intensive agriculture, erosion and climate change, among others.

A separate research study published in 2018 found that high atmospheric carbon dioxide impacts not only micronutrients, but also the protein and vitamin content of rice grains. The study found that in addition to protein, zinc and iron, carbon dioxide levels also lead to a decrease in vitamins B1, B2, B5 and B9. Although exact health outcomes are difficult to measure, given that rice is the primary food source For more than half of the world’s population, these deficiencies can present significant health risks.

Lewis H. Ziskaassociate professor of environmental health sciences at Columbia University’s Mailman School of Public Health, who is one of the study’s co-authors, writes in a related article blog post that these silent changes in plant physiology are often not part of mainstream discourse on the effects of increased carbon dioxide because they are difficult to contemplate. In an email interview, Ziska reiterated the importance of understanding these underlying changes. “The wider implications of a reduction in nutritional values ​​are enormous, not only in terms of human health from CO₂“The induced effects on proteins, vitamins and micronutrients, but the role that this will also play in the global food chain,” said Ziska, who also wrote a book on the impact of carbon dioxide on plants and the life.

Crop diversity can help improve nutrition

Speaking about a possible solution to this problem, ATREE’s Ravikanth admitted that it is a complex problem to solve, but one way to prepare for a nutritionally challenging future is to cultivate plants that better assimilate nutrients from the soil and provide optimal yields. Trials are underway at various research centers such as University of Agricultural Sciences, GKVK, Bengaluru.

Ziska added that at the policy level, crop lines with higher nutrient content should also be given incentives to encourage their cultivation.

“The Earth offers a wide range of genes among the plants we eat. Encouraging diversity both in time (crop rotation) and space (planting different crop lines in the same location) is absolutely essential to solving the nutrition problem,” Ziska said.

Natesan further added that approach is everything not only on the field but also at the plate. “Climate change mitigation requires all stakeholders to work together and find long-term solutions. But what we can do now is focus on the consumption of traditional grains and ensure a healthier diet, without chemical inputs, in order to address these deficiencies as early as possible, to the best of our ability,” she declared.

QUOTE:

Gojon A, Cassan O, Bach L, Lejay L, Martin A. The decline of plant mineral nutrition under increasing CO2: physiological and molecular aspects of a bad deal. Trends Plant Sci. February 2023; 28(2): 185-198. doi: 10.1016/j.tplants.2022.09.002. Published online November 3, 2022. PMID: 36336557.

Chunwu Zhu et al., Carbon dioxide (CO2) levels this century will alter the protein, micronutrient and vitamin content of rice grains, with potential health consequences for poorer, carbon-dependent countries. rice.Sci. Av.4, 2018.

Banner image: A vendor selling vegetables in Howrah, West Bengal. Photo by Biswarup Ganguly/Wikimedia Commons.